The prior art is well documented with examples of golf club swing training devices. The objective in each instance is to attempt to instruct a golfer in the proper technique associated with a golf swing, and in the hope of assisting a user in more completely connecting with a golf ball and driving the ball straighter and for longer distances.
The Adams Dixx Putter illustrates a computerized training system utilizing a micro inertial navigation system for identifying a correct putter face position in relation to impact with a ball. Relevant data is displayed on an LCD screen with the micro electro-mechanical system monitoring several factors relative to the users swing, including path, impact position, face angle, swing tempo and speed balance. A portable computer terminal is removable and substitutable with a practice weight.
U.S. Pat. No. 6,913,542, issued to Hu et al., discloses a golf club for showing swing condition having a shaft and a connected head with a striking face. Also illustrated is a battery powered and visible illuminant mounted on the head and exposed outside with an upward angle. A centrifugal switch is actuated by applying a centrifugal force and is mounted on the club head opposite the striking face for controlling a circuit between the battery and the illuminant. In this fashion, the illuminant will light upon application of a predetermined strength centrifugal force during swinging of the golf club for investigating the body harmony and strength-exerting condition of a golfer.
Other dynamic and velocity related measuring devices referenced include U.S. Patent Application Publication No. 2002/0173364, to Boscha, incorporating three force sensors built into a club head, a main electronic unit build into a shaft or grip, and a remotely positioned data acquisition, processing and displaying unit connected with the electronic units within the club via IR or RF transmitters. The information collected from the force sensors is employed to construct a dynamic analysis of swings and hits to correlate the results the results with actual movements of the ball, such being presented in display, graphical or digital form.
International Publication No. WO 2004/028649 teaches an apparatus for measuring swing velocity of a golf club head, as well as an advertising apparatus for golf training including the same, and which further employs a pair of magnetic sensors at different head and shaft locations. These interface with a micro controller and display for calculating and outputting either of a swing velocity and/or flying distance of the golf ball.
A further collection of pseudo club shaped golf swing training devices are illustrated in Wurster, U.S. Pat. No. 6,254,493, McGinty, U.S. Publication No. 2003/0032494 and Daechsel, U.S. Pat. No. 5,161,802. McGinty teaches a plurality of optical sensors adjacent a club face for detecting contact between the face and the golf ball, as well as electronics mounted within the head for processing the signals from the sensor for analyzing at least the location of the contact between the face and ball. The electronics further analyze whether the ball is tending to slice or hook by detecting lateral movement of the ball during contact with the club face
Wurster and Daechsel both teach golf swing practice devices (non functioning golf clubs) each including a weighted head portion attached to an elongated shaft. In the case of Wurster, a first laser module is mounted in the grip end of the shaft and directs a laser beam upwardly from the grip in coaxial alignment with the central axis of the shaft. A further pair of laser modules are mounted in the head of the training device for directing a pair of spaced parallel laser beams downwardly from the head in diametrically opposed direction from the beam emanating from the grip. The two beams projecting from the head are disposed in a common plane with a downward extension of the central axis of the shaft, such that a line drawn between the points of impact of the beams on the ground visually defines the footprint and thus the angular orientation of an imaginary club face.
Finally, Daechsel teaches another type of golf practice device exhibiting a shortened shaft with unique head weighted to equal the swing of a regular sized club. The head contains a battery for a light, which is centrally mounted with lens and iris to produce a focused, rectangular spot of light, parallel to the shaft center line. A combination level-and-centrifugal switch turns on the light spot when the shaft is level at the start of the down swing, and also as the head travels through the bottom of the swing. The rectangular light beam shows the path of the swing through a target ball, allowing the user to check the accuracy of the swing as well as the squareness of the club head to a target line. The target further comprises a golf ball with electronic receivers on either side in a straight line. The visual light path shows the direction of the swing, and the sound from the electronic receiver indicates to the golfer when a precise swing has been achieved. As repeat accuracy improves with practice, the light beam can be narrowed by adjusting the iris for still greater accuracy.